Mobile device usage continues to increase. In 2011, for example, mobile device traffic accounted for almost 7 percent of the total network traffic in the United States. Some of the biggest challenges facing mobile device users are imposed by energy constraints.
Energy constraints in mobile devices include, but are not limited to, slow improvements in battery capacity in view of the increasing power demands of modern mobile devices. For example, improvements in electronics (e.g., larger screens, increased number of sensors) and the processing power to execute more sophisticated software applications, account for some of the increased energy consumption by mobile devices. Data communications also contributes to the increased energy consumption by mobile devices. While just 10 years ago, mobile phones could last several days on a single battery charge, now it is common for users to have to recharge the battery in their mobile devices at least once a day, and often even more frequently. It is expected that battery capacity will struggle to keep up with energy consumption in mobile devices.